The present invention relates to a fresh gas supply device for a turbocharged piston internal combustion engine having fresh gas conduction elements. The device includes a compressed air connection which opens laterally into a tubular interior chamber and has a quantity regulating device, and an adjustable flap which is likewise arranged in the interior chamber and has the purpose of regulating the throughflow. The interior chamber may be bounded by a first end connection for receiving an inflow of charge air from an exhaust gas turbocharger to flow in, and a second end connection for flowing out the charge air from the exhaust gas turbocharger.
The fresh gas supply devices according to embodiments of the invention may be used to support exhaust gas turbochargers. The connected exhaust gas turbocharger cannot at times provide the necessary charge pressure, in particular in the lower rotational speed range of a turbocharged piston internal combustion engine, due to a lack of sufficient drive energy provided by exhaust gases. These circumstances are perceptible to a driver when accelerating out of a low rotational speed, for example when the vehicle starts from low speed or stopped, causing what is known as the so-called turbo deadpoint effect. In order to compensate for the turbo deadpoint effect, additional compressed air may be input into the intake manifold of the piston internal combustion engine from a compressed air supply of the motor vehicle, as necessary. In particular, many types of motor vehicle, such as utility or commercial vehicles or buses, have a compressed air network from which, for example, the pneumatic brake system is supplied.
International Patent Document WO 2005/064134 A1 discloses a generic fresh gas supply device for a turbocharged piston internal combustion engine. The charge air which is compressed by using an exhaust gas turbocharger passes into the cylinder space via an intake manifold. Furthermore, a compressed air line which is opened or closed by using a valve under electronic control opens laterally into the intake manifold. In order to compensate for the turbo deadpoint effect, the valve is opened so that the external compressed air, which is taken from the compressed air accumulator of the compressed air system, passes into the suction space. In order to prevent this additionally input compressed air from flowing back, a forcibly activated non-return valve is arranged in the intake manifold upstream of the turbocharger.
The additional fresh gas conduction devices according to this technical solution are an integral component of the fresh gas supply device and are configured on an engine-specific basis. Accordingly, when repairs are carried out it is thus necessary to exchange relatively large units. Designing variants with and without fresh gas conduction devices in a series of turbocharged piston internal combustion engines is also correspondingly more complex.
The exemplary embodiments of the present invention provide a fresh gas supply device for turbocharged internal combustion engines which can optionally be equipped with fresh gas conduction devices, and which can be used universally in turbocharged internal combustion engines.
The embodiments of the invention include utilizing fresh gas conduction elements which include a separate module, on whose housing the two end connections are located, for example in the form of line connections which are in addition also suitable as supporting elements for the module.
An advantage of the solution according to the exemplary embodiments of the invention is that turbocharged piston internal combustion engines can easily optionally be equipped with it. This is because the separate module can be coupled to the charge air duct when necessary. This also provides the possibility of retrofitting relatively old turbocharged piston internal combustion engines without providing any additional fresh gas conduction elements. Thanks to the modular design, it is possible to make available completely different fresh gas conduction elements which are respectively matched to assigned piston internal combustion engines. As a result, it is possible to adapt parameters, such as the flow rate of additional compressed air, the effective diameter at the valve and the like, to the corresponding piston internal combustion engine in a flexible way.
The two exemplary line connections may preferably be disposed on the housing of the module in the manner of a hose connection, in order to attach hose lines thereto using clip means or the like. In addition it is also possible to embody both line connections, in the manner of a pipe connection in order to attach pipelines thereto using pipe sleeves.
As an alternative to the two exemplary embodiments described above, it is also envisioned to embody at least one of the two line connections in the manner of a flange, in order to permit attachment using screws. The flange may preferably be arranged on the engine so that the module can be attached in a stable fashion to the piston internal combustion engine by using the flange.
In an exemplary embodiment, a quantity regulating device for actuating the flap for controlling the additional compressed air supply, an electromechanical adjustment device for the flap for actively controlling the position of the flap and a position determining device which is assigned thereto, are preferably installed within the housing of the module. These elements which are associated with the fresh gas conduction elements can be integrated into the housing in an installation-space-saving fashion. In addition to the compressed air ports, at least one electrical terminal for the electronic control unit, which may be likewise integrated in the housing, is also arranged on the outside of the housing. The electronic control unit can be connected to the operating voltage and, for example, a CAN bus of the vehicle electronic system via the electrical terminal.
According to a further exemplary embodiment according to the invention, the housing of the module is preferably formed in two parts. The integrated electronic control unit can preferably be arranged under a cover so as to be accessible from the outside in order, for example, to facilitate repair and maintenance.
An exemplary pressure pickup or sensor, whose pressure meter is arranged in the tubular interior chamber between the flap and the first end connection, may be preferably arranged on the electronic control unit. A further connection, via which a second pressure pickup is arranged in the tubular interior chamber between the flap and the second end connection, may also be connected. According to one exemplary embodiment of the invention, the pressure measured values which are acquired in this way are evaluated directly in the electronic control unit which, for this purpose, may include a computer in the form of a microprocessor which operates with corresponding operational and functional software. In another embodiment, it is also possible for the electronic control unit not to be equipped with such a computer and to contain just one power electronic system for actuating the quantity regulating device and the adjustment device. The rest of the control functions can in this case be carried out by using an external engine/vehicle electronic system in a decentralized fashion. Thus a distributed computing system as well as a dedicated computer may be used to perform control functions.
According to another exemplary embodiment of the invention, there is provision for an exchangeable, flow-influencing throttle to be installed in the compressed air line to the quantity regulating device. By selecting the throttle, for example by varying its position, it is possible to easily influence the flow parameter of the quantity regulating device.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.